Figure 3.

Distribution of Iron, Copper, and Zinc during Oocyte Maturation and Egg Activation in Wild-Type Drosophila

(A–C) Representative XFM images showing iron, copper, and zinc distribution in (A) an egg chamber around stage 10. Within an egg chamber, iron, copper, and zinc are all more concentrated in the oocyte (arrows); (B) a mature oocyte (stage 14). Zinc displays a more granulated distribution compared with iron and copper. Iron and copper display an even distribution. A granule of highly concentrated iron and copper (arrows) was observed at the anterior end of 8 of 14 of the wild-type mature oocytes, at approximately the location of the future micropyle, and egg anterior cytoplasm (see additional examples in Figure S9). The nature of this granule is unknown; (C) an activated but unfertilized egg. Zinc displays an even distribution. All samples are from ORP2 wild-type females. Scale bars, 100 μm. (A′–C′) Enlarged view of zinc distribution in (A–C). Dashed squares indicate enlarged regions. Scale bars, 10 μm.